The invention relates to a sealing arrangement in a rotating control valve of a pressure fluid-operated percussion device, to which percussion device a tool is mountable movable in its longitudinal direction relative to the frame of the percussion device, the percussion device containing a work chamber having a transmission piston mounted movable in the axial direction of the tool to compress the tool suddenly in its longitudinal direction by the pressure of the pressure fluid acting on the transmission piston to generate a stress pulse to the tool, and a control valve, to which inlet and outlet channels lead to conduct the pressure fluid to the percussion device and away from it and which has a rotatably mounted switch member with channels for connecting said inlet and outlet channels with the switch member to alternately conduct the pressure fluid through the channels to the work chamber and, correspondingly, to release the pressure fluid from the work chamber and in the inlet channel of the pressure fluid at the switch member side end thereof at least one sealing sleeve extending under the pressure of the pressure fluid toward the surface of the switch member for the purpose of sealing the inlet channel in relation to the switch member.
In pressure fluid-operated percussion devices, pressure fluid is fed into and removed from them through feed and discharge channels, respectively. To these feed and discharge channels pressure fluid hoses are typically connected to supply the pressure fluid into the feed pump and pressure fluid container.
For percussion operation, the feed and discharge of the pressure fluid in the percussion device is controlled with various control valves. The control valve may either move linearly or rotate. In rotating valves in particular, one practical problem is the sealing between the valve and channels, because all clearances cause leaks and leaks, in turn, cause a lower operating efficiency. Sealing also includes the problem that too tight a seal increases the rotation resistance of the valve and, thus, uses up the power of the device in vain and lowers its operating efficiency.
U.S. Pat. No. 7,290,622 discloses a solution in which separate sealing sleeves are used to seal the rotating control valve and the sealing sleeves are pushed against the surface of the control valve by the pressure of the pressure fluid so that no clearance remains between them. Adjusting the supply pressure of the sealing sleeve so as to keep the generated friction as small as possible is, to some extent, hard to do, even though a separate sealing sleeve structure is useful per se.